The present invention relates to a charged particle beam apparatus, and more particularly to a charged particle beam apparatus having a function of properly adjusting the focus of an image obtained by charged particle beam irradiation.
A charged particle beam apparatus such as a scanning electron microscope is suitable for measuring or observing patterns formed on a semiconductor wafer, which has been becoming finer. Incidentally, samples used for such a purpose have taken a shape extending more three-dimensionally as semiconductor wafers have been multilayered. For example, currently, deeper contact holes have been formed in a sample.